Coccobacilliform bodies were regularly demonstrable, in addition to H. gallinarum, in exudate from birds infected with a passage strain of the coryza of rapid onset and long duration (type III). Both agents were present throughout the entire course of the disease.
The characteristics of type III coryza were reproduced by injecting a mixture of the two agents. The behavior of each component was altered by the association, indicative of a synergistic relation.
Evidence that the coccobacilliform bodies might occasionally develop in birds infected with H. gallinarum following transfer by indirect contact was also obtained.
The combined action of the two infective agents adequately accounts for the etiology of this particular strain of type III coryza.